The society these days has a high degree of electrification. Most indoor environments have sockets to enable electric appliances to get electric power. Universal sockets compatible to specifications of varying receptacles and plugs of different countries also are available on the market that make electric interconnection possible among different specifications of plugs and sockets. The ordinary socket and portable universal socket have to conform to the safety regulations of the country they intend marketing. And improvement of safety features is a continuous effort pursued by producers to prevent users from hazards.
A conventional universal socket, such as R.O.C. publication No. 200919869 entitled “Universal socket” provides a ground socket compatible to varying specifications of many countries. It also has a neutral slot on the left side and a line slot on the right side at the front side of the socket. The slots are open type and can receive and accumulate dust and hairs and result in short circuit or even cause electric shock to users. As the universal socket has different slots to meet the specifications of varying countries, it has a greater chance of receiving external objects. To address this issue, there are techniques proposed to add a movable safety gate in the universal slot. Applicant has applied such a technique in China patent pub. No. 201238098 entitled “Sliding safety structure for power supply sockets”. In that case a power supply socket has a control seat, a safety gate and an elastic element with two ends pushing the control seat and safety gate. The control seat has a guiding rod to direct the safety gate. The elastic element butts two force receiving portions of the safety gate to close the path of a plug inserting to the socket electrode in regular conditions. When the plug electrodes are inserted into the socket, the two force receiving portions are pressed by the plug electrodes and the safety gate is pushed and slides. In the regular conditions it is at a closed position, the plug electrodes can be inserted into the socket electrodes. The aforesaid structure can enhance the safety of the socket. It also has a retaining portion to keep the safety gate at the closed position when the force receiving portions receives uneven forces. Therefore, it overcomes the flaw of the conventional safety structure that can be opened by a force from one side. Hence that application provides an adequate protection mechanism.
Although the aforesaid movable safety gate can protect the slots, the safety gate is movable and the closed condition can be achieved by pushing of the elastic element. Hence it still can be opened by purposely inserting a sharp tool (such as children inserting the slots with an article). As a result, the protection efficacy of the safety gate still has room for improvement.